The present invention relates to a laminate comprising a sliding member layer and a substrate layer, and more particularly to a laminate which has excellent sliding properties with window glass and abrasion resistance and is favorably used for a glass run channel and the like.
Thermoplastic olefin elastomers are lightweight, can be easily recycled and generate no harmful gas when incinerated, so that they are increasingly used for automobile parts, industrial mechanical parts, electric/electronic parts, building materials, etc. from the viewpoints conservation of energy, conservation of resources, and particularly in recent years, protection of global environment.
One example of the automobile parts is a glass run channel. The glass run channel is a guide member provided between window glass and window frame, and the glass run channel needs to facilitate a rise/fall (open/shut) operation of the window glass and to close the window glass tight (fluid-tight) on the window frame.
In the conventional glass run channel, a nylon film or the like to slide the window glass thereon is laminated onto a surface of a substrate made of, for example, a non-rigid synthetic resin (e.g., a non-rigid vinyl chloride resin) or an ethylene/propylene/diene copolymer rubber by using an adhesive. In order to decrease the contact area with the window glass, the nylon film is subjected to embossing before or after laminating.
The process for producing the glass run channel includes a laminating step using an adhesive, and hence the resulting glass run channel has a drawback that the skin layer is liable to peel off from the substrate. Moreover, the process is complicated because of a large number of steps.
Under such circumstances, the present inventors paid attention to the aforesaid thermoplastic olefin elastomers in order to solve such problems on the glass run channel as described above. However, when a thermoplastic olefin elastomer is used for a glass run channel as a single layer, the resulting glass run channel exhibits bad sliding properties with the window glass and is violently abraded.
Toward this problem, it is known that the sliding properties and the abrasion resistance are improved by adding a fatty acid amide to a thermoplastic olefin elastomer composition, as described in Japanese Patent Laid-Open Publication No. 176408/1997. Even by this method, however, improvement in the sliding properties and the abrasion resistance is not still satisfactory, and hence it is necessary to improve the sliding properties by adding silica or the like to roughen the surface of the skin layer. By the addition of silica or the like, however, the skin layer is hardened, and the manufactured product may have a crease when it is bent.
The present invention is intended to solve such problems associated with the prior art as described above, and it is an object of the invention to provide a laminate which has excellent sliding properties with window glass and excellent abrasion resistance and is favorably used for a glass run channel and the like.
The laminate according to the invention comprises a sliding member layer composed of a resin composition and a substrate layer composed of a thermoplastic olefin elastomer (A), and is obtained by co-extruding:
said resin composition which is obtained by melt kneading 100 parts by weight of a thermoplastic olefin elastomer (A), 10 to 250 parts by weight of an ultra-high-molecular weight polyolefin (B) (except a powder thereof having a particle diameter of 1 to 100 xcexcm) having an intrinsic viscosity (xcex7), as measured in a decalin solvent at 135xc2x0 C., of 1 to 40 dl/g, and 1 to 300 parts by weight of an inorganic or organic filler powder (C) having a particle diameter of 1 to 100 xcexcm in a twin-screw extruder, and
said thermoplastic olefin elastomer (A).
In the sliding member layer, the inorganic or organic filler powder (C) is homogeneously dispersed.
To the resin composition, a polyolefin resin (D) may be added in an amount of 1 to 150 parts by weight, and an organopolysiloxane (E) may be added in an amount of 1 to 50 parts by weight, each amount being based on 100 parts by weight of the thermoplastic olefin elastomer (A). Further, a fatty acid amide (F) may be added in an amount of 1 to 50 parts by weight, and a fluororubber (G) may be added in an amount of 1 to 20 parts by weight, each amount being based on 100 parts by weight of the thermoplastic olefin elastomer (A).
The inorganic or organic filler powder (C) is preferably an ultra-high-molecular weight polyolefin powder having an intrinsic viscosity (xcex7), as measured in a decalin solvent at 135xc2x0 C., of 1 to 40 dl/g.